Real-world insulin therapy in German type 2 diabetes mellitus patients: patient characteristics, treatment patterns, and insulin dosage

Background: A substantial share of type 2 diabetes mellitus (T2DM) patients receive insulin. However, little is known about the real-world treatment patterns around insulin initiation.

Methods: This was a retrospective claims data analysis. T2DM patients who initiated an insulin therapy between 01/01/2013 and 31/12/2015 were identified in the German AOK PLUS dataset. For validation of results, additional data on a similar T2DM patient population were collected in a Germany-wide medical chart review.

Results: A total of 284,878 T2DM patients were identified. Of these, 27,340 (9.6%) initiated an insulin treatment during the inclusion period (mean age: 72.2 years; 51.4% female). Mean/median weight and BMI of patients with available clinical data was 85.8/84.0 kg (SD:18.9) and 30.6/29.8 kg/m2 (SD:6.1), respectively at baseline. Mean/median HbA1c-value at baseline was 8.4/8.0% (SD: 1.8). Most commonly prescribed antidiabetic drugs (AD) within 6 months before insulin initiation were metformin (MET; 54.0%), DPP-4 inhibitors (DPP-4i; 37.6%), and sulfonylureas (SU; 29.5%). As high as 23.2% of the patients did not receive any AD prescription within 6 months before insulin initiation. A total of 10,953 of above 27,340 insulin starters (40.1%) initiated their insulin therapy without concomitant ADs (insulin monotherapy); 43% of these patients did not receive any AD before insulin initiation. Of the remaining 16,387 patients (59.9%), 4070 patients (14.9%) received MET only as concomitant AD, 6385 (23.4%) received MET plus at least one further AD, and 5932 (21.7%) received at least one further AD excluding MET. Throughout the first year of treatment, prescribed insulin dosage increased over time, resulting in approximately 43.3-77.9 IUs per observed patient day after 12 months of insulin treatment.

Conclusions: Characteristics of German T2DM patients initiating insulin deviate substantially from the average German population, especially in terms of weight. We identified an unexpectedly high number of patients without previous AD therapy receiving insulin monotherapy, which is not in line with the clinical guidelines.